Recently, privacy protection in compliance with the Personal Information Protection Law or the like has become more important. For example, in data mining utilizing big data, development of new drugs prescribed for rare diseases, statistical analyses including utilization of information obtained by a national census for state planning or the like, there is an increasing demand for processing data while concealing personal information. However, the stored precious data is often placed under security control and cannot be utilized effectively in market analysis and statistical analysis for planning, which are highly demanded, and the data is simply stored and remains a record.
One possible approach to the utilization of information while keeping personal information secret is to physically isolate a database including personal information and to perform a manual operation to allow access to necessary information. Techniques that can be considered include deleting items related to personal information from a database, encoding data when it is stored and decoding it to plaintext when it is manipulated, performing a manual access control operation to grant access rights only to the system administrator or the like, and to mask personal information so that individuals cannot be identified.
Techniques intended to perform function calculation or statistical processing while concealing personal information by using the approaches indicated above include those described in Non-patent literature 1 to 9, for example.